SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74ee61f92ab2cef5533d8cf685d13bfd2117eff8bec09df360b8e0a5f17a9bce' 
  AND token = 'IQtoG4qWChTjoV1Dg1BVmRozOz0cs3Jcwf/YXMMQsOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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