SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc929da2fba7d2e68d78b2cd70a9892c29bd44e67c48dcbc8780187d2555a65' 
  AND token = 'RIh/nnGGK5yvHxTaGrgeIMGQWexpIJReMY6rnBjgXv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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