SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eae8316acf2441ac793810ef3a6dc8597d868270fdf1a549dea8655dbbf799bb' 
  AND token = '5BVEALDb9oA5tPchh7qEjKyijdLlUy/RfDIf46DEXuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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