SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '172778357f832f02900062d031f646a6398648ee76566114ae7946a470ce75e4' 
  AND token = 'OQDJi2xEU/ZwHptovLOxuqicfO4AM1bW49vBXDq52rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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