SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea8173ef1314e423d09003665ab760fce7dc8dc26548315cf6f0090772d4c582' 
  AND token = 'WpMiUvem1K69mlalSzrUrhxwj2FzVB00N+lyIYZjIG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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