SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c3bf5d2e5057e64f49fc9e6b2bda3602b9807a83564709522c586f7296e2a539' 
  AND token = 'q6NBa32MVNDgTG+tGi1qQNJkUfNjkp3sCYf2fu9Ov/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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