SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c060bbd10e6055f13671231199c34a711154ead48b1b89152fb466c5ba0a592' 
  AND token = '6bCrwyH18an8bt0bbsuHmJrWAiKZX6s5vPXisKQIG8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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