SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '591681e2b4d0d966354ea30eaf8f972996cea45fd119193e57468bcb8cd04ccd' 
  AND token = 'jeKMJE9dmwuoa2/DuUpQa1yAjLeAiRQQq0SKEDkUvkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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