SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9dd723aa3b96bacef524cb9524dce35da3ccde81cca35e0f6fd3bd4b1df12698' 
  AND token = '91VglB1y+D+vzPlBWnwUoj28g8gKptdArzYnT2bnGCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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