SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '791c96dfe6988410962569253a7f31d874781be83f6d6c80cda929b9e994d355' 
  AND token = 'xSxyy/rt7zFDYUCvrIt07kcq5wJX3pz2jMhjOlAUdo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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