SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ef59c5a981b8a5fcfcc4eacea8371c375750472d5893d42b0b47adf30e4445e' 
  AND token = 'N7DVEd26F8CHzgKRoVg731MHlInJu72k2j4raPRDuPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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