SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '226bb1ae7734063f265c1f094b9368a6da4f3f2a3220e8f5591164ab5bc2fcfc' 
  AND token = '4iMCqQqhvG1BQcEVrKJ65sLZx1fzV4BwE47AoklKOAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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