SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aca5577a94499c7534c0f2b776e3159e69cacda3d336d896182cf010290a4ee6' 
  AND token = 'D8uY70dFfy4bSEADNZDLegtOGbPCkuNu0TSliZ/5Iac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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