SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c5fcf7fc23389270c68cdc75a74fc9cde82ba422244267ab33ce189360255c3' 
  AND token = 'dlTUPgxs0PAr2bpfHfUgibsuOnN/ZGe2krRksL+C/es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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