SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3027eb1d8974adba8f2bf1b088e24f1bb59e413c022ed268e0b8d1e14aa3504f' 
  AND token = 'G4OOsMiRHTpweeLrzaIdbYdjiTKXSYLjHrgXOuFrK0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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