SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da8e03901982c835a2cbf967a84d1a476bb0ffc375d15c186dff4bd8c86b2b2' 
  AND token = '/4dpCf3eULpLfR02jXXph0kz8VxD5otKsT++0dKv2CE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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