SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3dcc18fb3e6a225f5cb546979077f870e4756260ae50ff3ac5da2a1601d2d65' 
  AND token = 'P473MnA/TY/ypm0JA7p2UDKmwJX1VoJCg04GXjz0CNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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