SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfe102501e157e399a3d2674a2274787cf8bd9262e4a4a0e9852771b570ddd80' 
  AND token = 'sjLVq/45rmlH7IwuFcqeBj1b2RuBr4HheO4ufbAzF7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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