SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd974ede3be7153ec556822cbfb55c3924d547d8405c10a9c2fc3a756907062bb' 
  AND token = 'nhIyLftH144rZs1tBWTV4G+rjowkZ6UQlH04spcqBkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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