SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fe7a259e0cfa23e7fbb8211f583cba3b8fdd41dbae718ad793e70d169fb2c96' 
  AND token = 'ApDUtH0Ekakj3WlKubFiqYJ1efDhoCZqvpuR9m+JQvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}