SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feb7a464ba42f4b83f8cef8ddbeeee8a18467235f6bb8ab80daf2b4aae17fab1' 
  AND token = 'sGTK+Xo+El8wGJ9a/PsCe5nHXnVt45jQKWMCqWigf0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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