SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a42effa09f85599d508367109b0f9e444f75740c96be3b32253b2a312dacd5df' 
  AND token = 'NKQOfdALq3Kg5TFjLc5SZFaAoonGNYhTzRWRPJDDLiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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