SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b747e35f9e0ba27c3d3b2b9c21e2a81385860ea946ea16eb388f568108e88b47' 
  AND token = 'HLaXDHFydID076W9WIOZWqpc4YfJ3GowfJ6dJmrsOIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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