SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3d77ca6192baf113c17edfc1ec58733b913f3a8bdcde072811d902f176850d8' 
  AND token = 'aF3TBGA2PDsUU6cbRw6T/Muk6ms4YKniISm7wZQcUfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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