SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '443b6f4d9cf8d427590944426071c30dac44e26b13fff1dbdb44729ca85f7c81' 
  AND token = 'EkBfaNNEVYEpDWzv06IgxCLpBu96hT/ekey0cBaGxXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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