SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e21a8e7b6ab359eb33456c957e2bdce8320207e7bbd2162249b31f35944c2e56' 
  AND token = 'vKKbZjodeCZaWJiFYsLs2t5T22UhrDuwFtqPlkN5N3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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