SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '163f39c6eb1f49e74d99bc6485f40acc56d0995e80acd2432cfe7e353b1018f2' 
  AND token = 'lOwsH65BTxC1r4jr7kaYDtGZ3+OLc12vboKBpok+LXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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