SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fb9bfec1fd5c849c29b93db5497aebbed3b0ba596f6810e173539cfc34121466' 
  AND token = 'gIU0EsTsEuDyAPvGvAiHN96Qs/CUkLlcZrs8fOyn+iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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