SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47e9e726e43c5fe392c75068d4b8095987b83058d0e5bbeacfeb91f8885a56e5' 
  AND token = 'lVfJadcKp83cwSBJ2zD4EBF21ww5usCG7DqHCRpOKbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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