SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '287629377eafbf6ca761d37a36e0f18a6ab0882f0ceec4aa5a831839304009a9' 
  AND token = 'HLl5MRjFgUZp+k2pgo6s4BGZuoR666lKXb2SUG3KgcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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