SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb8ab8e3e7201477d082551acab11f98a01cb60e14f34bb1aa3ebb31e955791c' 
  AND token = 'OtFHrYM/llR1438cb/dVdEM4P/zrKQd0FKh9rripPds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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