SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc006200939c19aa14a98b8c6287f0ba62c43874253ef4e1cd98096f06ba4b39' 
  AND token = '6/fzkLk5nVYqBWJvYoBooZ2KZZH4Lmh1N+lI/uK/hGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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