SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8474fa08083e18f3c0cc6c9d40956f685e01452616487ab0a593c3cb92cb014d' 
  AND token = 'iMLpM2OIStl9HeoT7svdBjdhD/8F7siKhWEcZQjL+Jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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