SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '17f81b8aaed5445cf813bad1cb3651c0ccab92aef62fbdb49f2404a6b709172e' 
  AND token = 'xqQKuD/KPvl6BD0fxLUDVxDIVmlrp+3PXRsUoNND0fc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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