SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b62747c570aa6e99d25d17253c836bef5e44ea68387af382c8b74e6169e79f45' 
  AND token = 'UU4gAZS8icEgdbGpV9qjGCtvi27myjN8n1S+YXXhSHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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