SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f0c28415a896468d21bd332adda801ebc99f0fe94a5d7575df933fcc1fb6d13' 
  AND token = 'Ylk+2XrhLB4CjYJo6s+czPeukr85oR4v+6NyohxpJ7Q=' 
  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"
    }
  }
}