SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7713f3f23b854cd2c6b463ff6f98fbd374f814aa31f22ab2b1365c83902d3357' 
  AND token = 'RV8FVcpRO33uIrotVkGKCoR0HED1MgljoHp6hnlMvQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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