SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fc9408c78808e68be0753ee8995e188346154e9413941064036b199a413cf9eb' 
  AND token = 'UPzXVB8zTO8c554M+F+TUOM1qgj2+CjBEfmfoPt8cTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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