SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4f046dadef8f3f01bddb943495a4da247170d4801fdde4b458ed9caa8e77dfc' 
  AND token = '/qvwtzKkyxk6IOoSzx8+nSNm1VGYRANwHWqqoa93n84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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