SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f772c9f4b44ddf4cc2784f6e99d4b8cf71f91240791c67386198cdead6ea9375' 
  AND token = 'wRquvukYuvZrfF5OlNusCFRsNc6pdPqqUtP72vS5kio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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