SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '323b758cea8b41ff06c5b9011e7b394ce45b6a1daeaf1604a319d544652420ef' 
  AND token = 'ygMYAAEwvf6Imzdq1ziG6WLodBznrafRYskGF8XFCT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}