SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f890700836a88ed0fd59a7cbc140c5599ee073bedc4c53845d965310fce2bad7' 
  AND token = 'ObC4TYOIw2Q1R7Rw0K/+jZIqbdwtlARfVN9aoVgZ7bM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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