SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11e88c6603bfeecd9a76159c3204cce0bf915f461a0a5323d9a0ca0d6f913596' 
  AND token = 'Cb3FMxqoZzbJZ5ZdNCd3FO7TLi4uYXrh1/qZ3Cydqks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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