SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c621844f97f3acd30863bcf8d714c10d322cb6a04f36b95a13d88ae1111df834' 
  AND token = '/yzwoYALqD93zq/VhVA8gApQNLAKoOX5ofdKiKbDJeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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