SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40aeae89344035c61a0ca6393dd23229d20600c51b1737c9a5e1a7749dde4205' 
  AND token = 'PzefWcR7yaM48PpeHgi9Sia6cIJYzB8FdkZecbmlI5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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