SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c863314430525b4ff4cfdf80700739dbb2bd6b6536d86d4d43de443106ab30e0' 
  AND token = 'Vjkx+xlwzHO8XzhJEsJm2EOgbMQuoPAW+bd9KnhDt1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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