SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b461e854ec49e94130f2b55d6b829355b387fa0b57f022b5987db452a4c9ee21' 
  AND token = 'q501yz4uEnXPSfpTwhf5P00WEhXTO5Ykep0oSM8+hCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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