SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3cc04ec0dbf01cf2e552f0d0b648b01595749a97ae477da88b709266e3c22648' 
  AND token = '5I1VQwudibKjQb2ggh4AHHctRdT8+FBkGbAESbyn+zI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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