SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ada9d6cbd7aa00f7832cce79c5d6e54271e933d9c2705e02bc49add7ddfa16da' 
  AND token = 'eudPNJfBD/aGTw3EiJm54oJfPg8uZXPOoeHxegjgwx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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