SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35084ae365241155de3afe40db4cda939392c8efeb8d2ebf980170742fccdb7c' 
  AND token = 'BMn5sVeV3SPoGSCK/pqLU4Bj1P+7qSZZocxWXWyvxYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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