SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1ecb2f2f744b7bc1a1d460f233665d56c0ed118a1d8a711cba687f3e1ddb41b' 
  AND token = '7OQ46twfbqRoSDXWyNI2gBKlJ/3lVZsFK16PwK8Qq0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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