SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '307df982b12a7f242a1d12b7a0b6dd4c1f14c82e4f298b3cd796e6d8c5e72505' 
  AND token = 'mDS+lpeI/WieCz/gfS3bu5mfGpc6QKCLSuipLKvhcCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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