SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cbb4d104ff4a3c690ff7abec90b580e7f7ffdf5e046039d821cf44a937de920' 
  AND token = 'i8LM7vQaNEQeFfyyAVGF+bZNvYDlaTuVtqeLeLBLmFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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