SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12f45d65ae7455c732c8271aaaf985a017412ffd8cb439ad7a84e5d454504eb5' 
  AND token = 'u2cCiVY+vFCaIx1s6HduMM7sFhthHDgGnB0buXAKiwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}