SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5d21036d1e9a6cd7b5c5c1c1bd550d060c8b9a4bd40df2a5141653e8edb435e' 
  AND token = 'ULKk2wHrUikIT6BiltwESreicybux/csfpqyDFyhcnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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