SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c10fa1dcd3c8c557a73a35584b97de1dc491a63af4cefbadc391cff3e03e4c1' 
  AND token = 'FeKvnHC0nAoFuVOJcmp7fpZjj1/PCceUZY4I5MFhvT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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