SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '188267d55e2169eecc4d610155060005ff36ea5e48e6cd8dd94f7a0b5d11922e' 
  AND token = '6h2tBDxyE6gWoNH/L3XhxVkiTeE1EgeUCAbKMyO5jwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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