SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468ae893875e12dafaec2e08f28fb947d4883734a214f10a12882d24868b37b9' 
  AND token = 'JgckpDXwOZFbEubSvX3shv0Kf2mo8BI6g1kCCujgKgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}