SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '911beecf2d66f85dc1c07cd30563062c2fcd3ab376466c5ac1f32178c4d2a0b1' 
  AND token = '4PYW+Q3PRODyZhz4uPEjWzBUZ6zLENrLrpa2wJD/IQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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