SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b542ca8f4223386ecff1913968ac7e8158ef7f1dcfd3699fef3345b6b00b1227' 
  AND token = 'ez83eVfaEKsjKkTyPQqfYJlyVFn+xFJK51FCR8b+YxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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