SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b44b9cf0623368f395318d282f7bdf2db741148b9e566d4945c492e77e68448b' 
  AND token = 'tLtViN5r5gCnTho2LBe3grAXJMvjClVBsHnuyup64c4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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