SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a48a52720acc6a1e62c238caf68dd4b5e0331d1b87fa56f4eed82efe2221676' 
  AND token = 'MlNGIyHBBXAoGR6I/XCEhbj0+91prLB6lriZ9zETDYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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