SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '945277f0c365b8af057c4db742d32629839f265a437158fea2911e7b278c5834' 
  AND token = 'xL0rqoFwLDPCvDUCHEgwQ8WOcqezGyNUYNvFDJzzAAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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