SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dc6684b558fcbd5761beac1a9c0bb90f1ca240353d67246c99637a7a8ffc275' 
  AND token = 'dHAtfu+le1M/q1q7zam7ttC6BLsgCZfLXYpkVwr3kvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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