SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b59e271e979da5fd58a37799dfc22b710c0c884016551b2978260dc506e24a58' 
  AND token = 'CEJmeDxuA7eBG1ERcYAx38nd7tSKDmOuCKvOYBaiHT8=' 
  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"
    }
  }
}