SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2c44076f2d91347642e0b2668c99d4e23230f027366171f4ea0ed3f7a6efb2b' 
  AND token = 'nFXj6CULeFZbOS40zmZDrdVGBraHAGVfKNrrnKHlvKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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