SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1894a19c9bac533e7475db30bb5f3836ea529dda7db2a7a62ba04465431aae' 
  AND token = '1JHzB/Yw0q1yWJ9VWTERGN+GzD/Qj4qGVc6huQcLGCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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