SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '356849ed5eea2ed858514efde31a77a049a4330918bf85d1fc8d67df3d503821' 
  AND token = 'cQ7ryWIxngpDR6OxvTm9oKdDWD1lgBDwsRm9lK1pv8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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