SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a87335f3e6909f85dfaabb8fd241736341c38356bf6e26b4cded48840205f74' 
  AND token = 'uDifrLDS+2pbxGte+B/1gB8+IF7RrGVFZpKC4qAYMbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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