SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f25f89f891c52f9ef566fe0c8d2ea56fa51205228151ad3c3ecf7013c28441b' 
  AND token = '8EfC51UFFqIcR8PKfnDEK/SOXU2u3rq7LGVIvkNu1Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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