SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92a75d24a8f6e9eed64bbce66c4905e40f5e6744ad2101ada5bfda1529c4e329' 
  AND token = 'zkqmqClaEUyTncv8AluZ/aprMsK9NJZmMGQ5L+Gw6xE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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