SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e77e8da0a263f04a4ddaf4a2ffbeb9b806b0cd38d308d4e546f182bcec3ac0a5' 
  AND token = 'NFaOcJ6Td54HMNaEfQSGe5z4py8SxOFuRIWP4SZ60Co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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