SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c92520d7dbe07c50f25beb85484ea8862abeb27e9157ccc0f8f76ee4d47546a' 
  AND token = 'SjnMOvna4BIjVddnGqe8GHmpiYNR/GKsHpFQU71AvG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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