SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62dedbcbe1391efc3b33485e497440fe2bb6edac888f75c20055d936faa412d9' 
  AND token = 'lnmiDTOpz8KJm1xWNpzo0V+PaERjJBTwxgfzN2UhAOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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