SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dee29d6bdcd6b8a3cc0f296e44823b431d669825037aa62f814b05045e2a0b28' 
  AND token = 'zRDYrHJj9bfwbrtYQynGbMN+oIEy/mhXVdWBgm7AW44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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