SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'bd52367736a68d091fd87466c55985ec898baf7c59c6a8bbc1f00ebe5ccb8794' 
  AND token = 'mvattUJhfCewCNwVUierIZg0LunCcuFxl6qIhuR6ETM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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