SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '52116ef0cee03fe9a8dd7d9022623d678e6b15012255403a8d8535142469ff73' 
  AND token = 'Is/iezqIXI0E7fTfg4NeGltRmzVH1hloOrpdiUnHevg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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