SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '809fdd741a0fd63aa625c7187601b7d40bf96e997204d57b27f312db025af578' 
  AND token = 'nXlJgOfYdKEAx1+Uwopik+sycUZW66P2HYuXimeapcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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